1. Field of the Invention
The present invention relates to a data reproduction device and a method for controlling the device which reproduces data from a recording medium having an error correction area formed therein which area includes only error correction codes for correcting data recorded in a data area.
2. Description of the Related Art
As one of applications of an optical disk, a ROM (Read Only Media) has been practically utilized which ROM is used only for reproducing data which is recorded in advance in the disk. In the field of magnet-optical disk, such a ROM is now being considered to be standardized.
A format of the ROM is arranged, to raise the reliability of the disk device, in such a way that an error correction code is added to the data recorded in the data area and that another error correction code is generated by another method for generating the code (referred to as parity code below) so that a parity area is formed in the recording medium which parity area includes only the parity code.
In the event wherein at the time of data reproducing operation, when the data error is not completely corrected by the error correction code added to the recording data, the error of the data is further corrected by the parity code corresponding to the data read from the parity area.
However, the arrangement mentioned above is involved in the following problems.
That is, at the time of data correction with the use of the parity code when reproducing the data, it becomes necessary to move the optical head for reproducing the data to the parity area where the parity code is recorded as a result of which it takes much time to access to the data.
To cope with this problem, it is proposed to prepare two optical heads arranged in such a way that one of the heads is used to access to the data area while the other head is used to access to the parity area. However, such an arrangement very complicated and bulky, which makes the disk device very expensive and impedes the realization of a compact structure of the disk device.